I'm new to scripting for InDesign and InCopy, and I'm stuck now with a problem. I want to add textframes or rectangles to a (new) assignment with javascript. I found out how to create an assignment, and how to make a incx document, however it comes in unassigned incopy items, and I can't find a way to place it into my new assignment.

To create an assignment I use:
var myAssignment = jobDoc.assignments.add(aName);

And to create an incx file I use:
aTextframe.exportFile(ExportFormat.INCOPY_DOCUMENT, File("/test.incx"));

Both work, but now I need a way to place the incx into myAssignment. How can this be done?